Preparation and characterization of pickering emulsion stabilized by hordein-chitosan complex particles

In this study, hordein-chitosan complex particles (HCPs) were prepared using anti-solvent precipitation method. The addition of chitosan led to the increase in the particle diameter and zeta-potential as well as the gradual decrease in fluorescence intensity values of HCPs, indicating chitosan absorbed onto the surface of hordein particles. Fourier transform infrared spectra of HCPs showed the significant shifts of peak position for O–H stretching vibration, amide Ⅰ and Ⅱ bands after addition of chitosan, suggesting the formation of hydrogen bonds and hydrophobic interactions between hordein and chitosan. Three-phase contact angle (θo/w) of HCPs revealed the excellent wettability (θo/w = 89.3 ± 1°) of particles when the mass ratio of hordein to chitosan was 2:1 (HCPs2:1). Oil-in-water Pickering emulsions (Caprylic/Capric Triacylglyceride as oil phase) stabilized by HCPs2:1 were further prepared. Confocal laser scanning microscope images indicated that HCPs absorbed at the oil/water interface and formed a dense steric barrier on the surface of spherical oil droplets. Higher oil fractions (50% and 60%) led to the formation of stable Pickering emulsion gels, which showed long-term storage stability. This study provides a new solution to accelerate the application of hordein-based Pickering emulsions in food industry. [Display omitted] •Chitosan was capable of absorbing onto the surface of hordein particles via hydrogen bonds and hydrophobic interactions.•Surface wettability of hordein particles were tuned in the presence of chitosan.•Pickering emulsions stabilized by HCPs had excellent storage stability.